“Why premeditated? Because the victim was stuffed into a bag. It shows planning,” Mr Benny said.

The suitcase displayed at a police station in Nusa Dua, Bali. Photo: AFP

The American couple have still not been questioned because they are waiting for a lawyer. But Mr Benny said: “Even without confessions or a statement, based on the evidence collected — which includes CCTV footage, fingerprints, the items used, the bag — it all points to them as the perpetrators.”

Advertisement

He said both would undergo psychological testing for “supporting evidence”, but he added: “there's no psychological aspect; it's pure premeditated murder”.

Police allege the couple bludgeoned Heather’s mother, Sheila Von Wiese Mack, 62, to death with a heavy glass object before putting the body in a grey suitcase, wrapping that in a hotel bed sheet and loading it into a pre-ordered taxi.

Tommy Schaefer is escorted to the police station for questioning. Photo: AP

They say Mrs Mack was killed on Tuesday morning, after which police say the pair mopped up the blood with towels and sheets, hid the evidence, then fled the hotel for the airport.

They were arrested on Wednesday morning sleeping at a hotel after having unsuccessfully tried to obtain new passports at the airport.